In the prior art, different types of driver assistance systems are known which essentially share the common feature that they serve to ease the burden on the driver in traffic events. Driver assistance systems of this type are often also capable of carrying out measures which extend beyond a pure comfort effect and which, in particular, avert hazards. Examples of these include such things as situation-related warning outputs to the driver or even interventions in the vehicle control. The necessary information acquisition is increasingly based on vehicle-to-X communication which, however, relies on processing-intensive encoding and decoding methods in order to ensure the necessary data security and therefore protect against maliciously manipulated vehicle-to-X messages. It is also known in the prior art for the content of a received vehicle-to-X message to be validated by means of environment sensors, so that the comparatively processing-intensive decoding of the corresponding vehicle-to-X message can be dispensed with.
In this context, DE 10 2007 058 192 A1, which is incorporated by reference describes a central control device for a plurality of assistance systems provided in a motor vehicle which are at least partially equipped with environment sensors, wherein, according to DE 10 2007 058 192 A1, a telematics system is also understood as an environment sensor. The central control device is connected at data level to the individual assistance systems and checks the plausibility of the information from individual environment sensors by means of the information from other environment sensors. For example, the image information from a camera can confirm the distance measurement of a radar sensor. Individual sensor information can thus be confirmed and is present in redundant form.
DE 10 2012 221 260 A1, which is incorporated by reference discloses a method for determining the position of objects in road traffic. A transceiver initially transmits wireless communication signals. These signals are at least partially reflected in their propagation area on the objects located there and are finally received once more by the transceiver as reflection signals. The transceiver then determines the distance and the direction of the object in relation to the transceiver from different phase information of the reflection signals. The distance is determined from the phase difference in two reflection signals transmitted and received once more on different frequencies. The direction, on the other hand, is determined from the phase difference in a reflection signal which is received by means of two spatially slightly offset antenna elements. In the latter case, the phase difference is the phase difference that is generated by the spacing of the two antenna elements. According to DE 10 2012 221 260 A1, it is not necessary for the communication signals and the reflection signals to be transmitted and received by the same transceiver. Instead, it is also possible for a first transceiver to transmit the communication signals and a second transceiver to receive the reflection signals.
A method and a system for validating a vehicle-to-X message are known from DE 10 2011 079 052 A1, which is incorporated by reference. A wirelessly transmitted vehicle-to-X message is received by an antenna arrangement having at least two antenna elements, wherein the electromagnetic field strength of the vehicle-to-X message is acquired by the antenna elements with different power densities due to the different, direction-dependent receive characteristics of the antenna elements. The receiver determines a relative position of the transmitter in relation to the receiver from the ratio of the different power densities in the antenna elements. The vehicle-to-X message furthermore contains an absolute position of the transmitter based on GPS data from which the receiver of the vehicle-to-X message calculates a further relative position of the transmitter in relation to the receiver via its own absolute position. The received vehicle-to-X message can then be validated by means of a comparison of the two relative positions if the two positions match one another, or can be rejected if the positions differ from one another.
However, the methods, apparatuses and systems known in the prior art are disadvantageous because they always require additional sensor devices or measuring devices, such as a multi-element directional antenna, in order to validate a received communication signal, or must perform a processing-intensive decoding, which in turn requires correspondingly powerful and therefore expensive processing modules.